Boron Nitride Nanosheets Modified with Polydopamine and Polyimide Nanofibers as Flexible Thermal Management Materials
Fan Xie, Qiyang Dai, Longhai Zhuo, Chaobin He, Xiyi Dai, Qiaoling Liu, Haitao Wei, Zhaoqing Lu
Abstract
Inspired by the structure and production process of textiles, a zigzag aligned structural design was proposed to fabricate flexible thermally conductive nanocomposites via a facile, scalable lamination process of electrospun polyimide (PI) nanofibers. More specifically, polydopamine (PDA) was used as a modifier to functionalize boron nitride nanosheets (BNNS), and the p -BNNS/PI nanofilm was prepared using the electrostatic spinning technique. Subsequently, the nanofilm was rolled into vertically oriented cylinders, and vacuum-assisted impregnation of polydimethylsiloxane (PDMS) was carried out, resulting in the construction of p -BNNS/PI/PDMS nanocomposites. The obtained nanocomposites not only demonstrated strong anisotropy and significantly enhanced thermal conductivity but also possessed excellent electrical insulation performance. The nanocomposites with 10 wt % p -BNNS exhibited both an ultrahigh out-of-plane thermal conductivity of 1.26 W/m K and a high volume resistivity of approximately 10 15 Ω cm. Additionally, the nanofilm maintained excellent flexibility and remained intact even after kneading for 60 s while exhibiting a maximum tensile strength of 29.7 MPa. This work provided an effective method to establish a continuous thermal conductive network and further expanded the thermal management applications of polymer-based nanocomposites in electronic packaging and other fields.